Data point averaging for computational fluid dynamics data

ABSTRACT

A system and method for generating fluid flow parameter data for use in aerodynamic heating analysis. Computational fluid dynamics data is generated for a number of points in an area on a surface to be analyzed. Sub-areas corresponding to areas of the surface for which an aerodynamic heating analysis is to be performed are identified. A computer system automatically determines a sub-set of the number of points corresponding to each of the number of sub-areas and determines a value for each of the number of sub-areas using the data for the sub-set of points corresponding to each of the number of sub-areas. The value is determined as an average of the data for the sub-set of points corresponding to each of the number of sub-areas. The resulting parameter values then may be used to perform an aerodynamic heating analysis.

GOVERNMENT LICENSE RIGHTS

This invention was made with Government support under Boeing subcontract6000132079 awarded by United Space Alliance under prime contractNNJ06VA01C awarded by NASA. The Government has certain rights in thisinvention.

BACKGROUND INFORMATION

1. Field

The present disclosure relates generally to systems and methods forgenerating data by a computer simulation of a flow of fluid over asurface, and more particularly to systems and methods for generatingsuch data for sub-areas of a surface from data generated for a number ofpoints on an area of the surface.

2. Background

Computational fluid dynamics is a branch of fluid dynamics.Computational fluid dynamics uses numerical methods and algorithms tosolve and analyze problems that involve fluid flows. For example,computers may be used to perform the calculations required to simulatethe interaction of liquids and gasses with a surface defined by boundaryconditions. The result of these calculations may be data for a number ofpoints in an area of the surface. For example, the area of the surfacemay be a two-dimensional planar area of the surface. Data generated forthe number of points may include values for various properties relatedto fluid flow over the surface. For example, such properties may includetemperature, pressure, heat flux, velocity, and other properties.

Aerodynamic heating is the heating of a solid body produced by thefrictional interactions and passage of fluid about the body. Aerodynamicheating analysis may be performed by a computer using a thermal model ofthe body and computational fluid dynamics data describing the propertiesof fluid flows across the body.

Aerodynamic heating of aerospace vehicles is of particular interest. Forexample, aerospace vehicles may include aircraft and spacecraft that aredesigned to reenter the atmosphere. Aerodynamic heating occurs when airpasses over an aerospace vehicle during vehicle transit, ascent,descent, and reentry. Aerodynamic heating of an aerospace vehicle is afunction of various factors. For example, aerodynamic heating of anaerospace vehicle is a function of such factors as reentry angle, speed,air density, thermal protection system material properties, vehicleconfiguration, and other factors.

Depending on the vehicle configuration and thermal protection systemmaterial properties, aerodynamic heating typically increases as the airincreases in density and as the air passes more quickly over thevehicle. The increase in the speed at which air passes over the vehicletypically occurs as the speed of the vehicle increases. Aerodynamicheating temperatures encountered during aerospace vehicle transit,ascent, descent, and reentry can range between approximately 600 degreesCelsius (“° C.”) and approximately 1930° C., approximately between 600°F. and 3500° F.

The degree of aerodynamic heating experienced by an aerospace vehiclemay affect various characteristics of the vehicle. For example,aerodynamic heating considerations may affect the performance of avehicle, which types of thermal protection system configurations andmaterials are needed for the vehicle, how often inspections andmaintenance are needed, and whether the vehicle should be reconfigured,repaired, and/or replaced.

The effects of aerodynamic heating on a vehicle structure may becontrolled to within acceptable limits through the use of a thermalprotection system. For example, a thermal protection system may be usedon an aerospace vehicle that travels at supersonic, hypersonic,exo-orbital, and exo-atmospheric speeds. A thermal protection systemalso may be used on a spacecraft that reenters the atmosphere.

For example, a thermal protection system for a space shuttle includes abarrier to protect the space shuttle from aerodynamic heating when thespace shuttle renters the atmosphere. The temperatures encountered bythe space shuttle during reentry may be about 1650° C. degrees or more.The thermal protection system for the space shuttle includes a materialthat covers the surface of the space shuttle that is exposed to airduring reentry. The thermal protection system may be implemented usingvarious materials. For example, such materials may include one or moreof an integrated and integral ceramic matrix composite material (CMC), apolymeric matrix composite material (PMC), and such materials that areclad with ablative and high-temperature coating materials.

In the space shuttle example, the thermal protection system takes theform of tiles that are attached to the surfaces of the space shuttlethat are exposed to heating during reentry. For example, these tiles maybe located on the lower surface of the space shuttle. Thermal protectionsystem tiles also may be located at other suitable places on the spaceshuttle. The tiles on the space shuttle are made of an insulatingmaterial known to those having knowledge in the relevant arts to be asilca glass fiber material. The many types and configuration of suchtiles absorb and radiate heat while minimizing heat load conduction tothe aluminum airframe.

Unintended features or anomalies may occur in an aerospace vehiclethermal protection system. For example, such unintended features oranomalies may occur in the thermal protection system tiles, in thematerials used to attach the tiles to the space shuttle surface, and inthe materials used to seal and fill gaps and channels between the tiles.These unintended features or anomalies may occur as nicks, dings, orscrapes in the tiles and/or as foreign objects embedded in or betweenthe tiles. Such unintended features or anomalies may arise or occurduring pre-flight preparation or during operation of aerospace vehiclessuch as the space shuttle. Such undesirable features or anomalies mayaffect the aerodynamic characteristics and performance of the thermalprotection system. Similar issues may arise in other types of thermalprotection systems, using other types of materials, and that are used inother types of aerospace vehicles.

Accordingly, it would be advantageous to have a method and apparatus,which takes into account one or more of the issues discussed above aswell as possibly other issues.

SUMMARY

A method and apparatus for generating data for use in aerodynamicheating analysis includes receiving into a computer system anidentification of computational fluid dynamic data. The computationalfluid dynamic data includes data for a number of points in an area. Thedata is generated by a computer simulation of a flow of fluid over asurface corresponding to the area. An identification of a number ofsub-areas of the area is also received into the computer system. Thecomputer system determines a sub-set of the number of pointscorresponding to each of the number of sub-areas. The computer systemthen determines a value for each of the number of sub-areas using thedata for the sub-set of points corresponding to each of the number ofsub-areas. The value is an average of the data for the sub-set of pointscorresponding to each of the number of sub-areas.

A method of aerodynamic analysis of a surface includes receiving into acomputer system surface condition information from a surface conditiondetector. Data for a number of points in an area are identified into thecomputer system. The data is generated by a computer simulation of aflow of fluid over the surface corresponding to the area for expectedenvironmental conditions. An average of the data for the number ofpoints is determined by the computer system. Whether the surface isflight worthy may be assessed using the surface condition informationand the average of the data.

The features, functions, and advantages can be achieved independently invarious embodiments of the present disclosure or may be combined in yetother embodiments in which further details can be seen with reference tothe following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the advantageousembodiments are set forth in the appended claims. The advantageousembodiments, however, as well as a preferred mode of use, furtherobjectives and advantages thereof, will best be understood by referenceto the following detailed description of an advantageous embodiment ofthe present disclosure when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is an illustration of an aerospace vehicle and spacecraftmanufacturing and service method in accordance with an advantageousembodiment;

FIG. 2 is a block diagram of a vehicle in accordance with anadvantageous embodiment;

FIG. 3 is a block diagram of an aerodynamic analysis environment inaccordance with an advantageous embodiment;

FIG. 4 is an illustration of a data processing system in accordance withan advantageous embodiment;

FIG. 5 is an illustration of a space shuttle in accordance with anadvantageous embodiment;

FIG. 6 is a schematic illustration of data points for an areacorresponding to a portion of the lower surface of the space shuttle ofFIG. 5 in accordance with an advantageous embodiment;

FIG. 7 illustrates determining sub-areas and data points in thesub-areas in accordance with an advantageous embodiment;

FIG. 8 illustrates determining a number of sub-areas and data points inthe number of sub-areas in accordance with another advantageousembodiment;

FIG. 9 is a flowchart of a method for determining average computationalfluid dynamic values for sub-areas in accordance with an advantageousembodiment; and

FIG. 10 is a flowchart of a method for analyzing and changing a surfacein accordance with an advantageous embodiment.

DETAILED DESCRIPTION

Referring more particularly to the drawings, embodiments of thedisclosure may be described in the context of the aerospace vehicle andspacecraft manufacturing and service method 100 as shown in FIG. 1 andvehicle 200 as shown in FIG. 2. Turning first to FIG. 1, an illustrationof an aerospace vehicle and spacecraft manufacturing and service methodis depicted in accordance with an advantageous embodiment. Duringpre-production, example aerospace vehicle and spacecraft manufacturingand service method 100 may include specification and design 102 ofvehicle 200 in FIG. 2 and material procurement 104. During production,component and subassembly manufacturing 106 and system integration 108of vehicle 200 in FIG. 2 takes place. Thereafter, vehicle 200 in FIG. 2may go through certification and delivery 110 in order to be placed inservice 112. While in service by a customer, vehicle 200 in FIG. 2 isscheduled for routine maintenance and service 114, which may includemodification, repair, reconfiguration, refurbishment, and othermaintenance or service.

Each of the processes of aerospace vehicle and spacecraft manufacturingand service method 100 may be performed or carried out by a systemintegrator, a third party, and/or an operator. In these examples, theoperator may be a customer. For the purposes of this description, asystem integrator may include, without limitation, any number ofaerospace vehicle and spacecraft manufacturers and major-systemsubcontractors. A third party may include, without limitation, anynumber of venders, subcontractors, and suppliers. An operator mayinclude, without limitation, a company, a military entity, a serviceorganization, and so on.

With reference now to FIG. 2, an illustration of a vehicle is depictedin which an advantageous embodiment may be implemented. For example,vehicle 200 may be an aerospace vehicle or a spacecraft. In thisillustrative example, spacecraft 200 is produced by aerospace vehicleand spacecraft manufacturing and service method 100 in FIG. 1. Vehicle200 may include frame 202 with a plurality of systems 204 and interior206.

Examples of plurality of systems 204 include one or more of propulsionsystem 208, electrical system 210, hydraulic system 212, environmentalsystem 214, and thermal protection system 216. Although an aerospaceexample is shown, different advantageous embodiments may be applied toother industries, such as the automotive industry.

The different advantageous embodiments recognize and take into account anumber of different considerations. For example, the differentadvantageous embodiments recognize and take into account thataerodynamic heating analysis of a body requires information describingthe flow of fluid across a surface of the body. This information may beavailable in the form of computational fluid dynamics data.Computational fluid dynamics data is generated by computer simulation ofa flow of fluid over the surface of the body. Computational fluiddynamics data is calculated for many points in areas defined on thesurface.

The different advantageous embodiments also recognize and take intoaccount that aerodynamic heating analysis may employ thermal models of abody. These models define the thermal characteristics of massesrepresented by two-dimensional areas across the surface of the body.However, there is not a one-to-one correspondence between the areas usedfor aerodynamic heating analysis and the data points generated bycomputational fluid dynamics simulation. Many points of computationalfluid dynamics data may be generated for a single area modeled foraerodynamic heating analysis. For example, computational fluid dynamicsdata may be generated for points separated by a few inches across asurface. A thermal model of the same surface may model the thermalconditions for areas of the surface that are a number of feet across.Thus, computational fluid dynamics data is not directly compatible foruse in aerodynamic heating analysis using a thermal model.

The different advantageous embodiments recognize and take into accountthat currently fluid flow data for use in aerodynamic heating analysisis obtained manually from available computational fluid dynamics data.For example, currently a skilled technician will visually inspectavailable computational fluid dynamics data for an area for which anaerodynamic heating analysis is to be performed. This area may includemany points of computational fluid dynamics data. From this availabledata, the technician will select manually the data to be used in theaerodynamic heating analysis. For example, the technician may selectdata from one point in the area as being representative of computationalfluid dynamics data across the area. Alternatively, the technician maymentally summarize the computational fluid dynamics data for many pointsin the area to derive the data to be used for the aerodynamic heatinganalysis.

The different advantageous embodiments recognize and take into accountthat current manual methods for obtaining fluid flow data for use inaerodynamic heating analysis have limitations. For example, manualselection of data is time consuming. Furthermore, manual selection ofdata may not always result in optimal data selection. Manual dataselection relies on the skill of technicians for extractingcomputational fluid dynamics data for use in an aerodynamic heatinganalysis. Thus, the accuracy and consistency of aerodynamic heatinganalysis relying on such a method for data selection is limited.

The different advantageous embodiments recognize and take into accountthe desirability of fast and accurate aerodynamic heating analysis. Forexample, fast and accurate aerodynamic heating analysis is particularlydesirable for aerospace vehicle operations. Fast and accurateaerodynamic heating analysis may be desired to determine the effects offeatures or anomalies on a vehicle thermal protection system in order tomake timely and accurate repairs.

It would be advantageous to enable effective repairs to be made tocorrect such features or anomalies before, during, and after operationof aerospace vehicles. It also would be advantageous to enable suchrepairs in a way that minimizes the time required to assess variousrepair approaches and which maximizes the accuracy of the design forsuch repairs. Another advantageous capability would be to increase theprecision with which such repairs can be designed and affected in shorttime periods. Such advantageous capabilities are especially importantfor operational and in use aerospace vehicles.

For example, consider the case of any type of orbital aerospace vehiclethat has ascended to orbit, and for which such undesirable features oranomalies are discovered. Such missions have strict time limitations dueto airframe limitations and limited fuel and crew provisions.Accordingly, whenever possible, it is imperative that a repair bedesigned and effected on-orbit as quickly as possible so as not tojeopardize the mission success.

Any such repair typically may be made after an analysis of the thermalprotection system in the context of the operational environment,including the reentry environment. That analysis may include, amongother considerations, a rapid but effective analysis of the airstreamflow over the thermal protection system. Such reentry and operationalairstream data for aerospace vehicles often is available incomputational fluid dynamics performance libraries and databases for thelarger aerospace vehicle. Such libraries may contain computational fluiddynamics data for many points across the surface of the vehicle.However, for a rapid and effective repair, specific subsets of thecomputational fluid dynamics performance data must be identified inorder for an accurate aerodynamic heating analysis to be made.

Furthermore, the different advantageous embodiments also recognize andtake into account that the inherent inaccuracy of selectingcomputational fluid dynamics data manually for use in aerodynamicheating analysis is recognized by designers of thermal protectionsystems and other aerospace vehicle components. This situation causesaerospace vehicle components to be designed with higher aerodynamicheating thresholds than would be needed if more accurate calculationscould be performed.

Obtaining accurate data for use in aerodynamic heating analysis presentsa technical problem. Computational fluid dynamics data is available foruse in aerodynamic heating analysis, but it is not available in a usefulform. Currently, non-technical manual methods are used to obtain thefluid flow parameter data for use in aerodynamic heating analysis fromsuch computational fluid dynamics data. However, this technical problemcalls for a technical solution in which aerodynamic heating analysis maybe performed more rapidly, accurately, and consistently in an automatedmanner.

Thus, the advantageous embodiments provide a technical method andapparatus for generating fluid flow parameter data for use inaerodynamic heating analysis. For example, in accordance with anadvantageous embodiment computational fluid dynamics data is generatedfor a number of points in an area on a surface to be analyzed. Sub-areasare identified. For example, the sub-areas may correspond to areas ofthe surface for which an aerodynamic heating analysis is to beperformed. Responsive to identifying the sub-areas, a computer systemautomatically determines a sub-set of the number of points correspondingto each of the number of sub-areas. The computer system then determinesa value for each of the number of sub-areas using the data for thesub-set of points corresponding to each of the number of sub-areas. Thevalue is determined by the computer system automatically as an averageof the data for the sub-set of points corresponding to each of thenumber of sub-areas. The resulting accurately determined computationalfluid dynamics parameter values then may be used to perform a moreaccurate aerodynamic heating analysis. Changes to the surface may bemade in response to the results of such an accurate aerodynamic heatinganalysis. For example, the results may be used to change the surfacedesign or to affect a repair of the surface.

With reference now to FIG. 3, an illustration of an aerodynamic analysisenvironment is depicted in accordance with an advantageous embodiment.Aerodynamic analysis environment 300 may be used to perform aerodynamicanalysis 302 on structure 304. For example, structure 304 may be vehicle200 in FIG. 2. Alternatively, structure 304 may be a portion of vehicle200 in FIG. 2. Structure 304 may be aerospace vehicle 306 or spacecraft308. Alternatively, structure 304 may be a portion of aerospace vehicle306 or spacecraft 308. For example, structure 304 may be a portion of athermal protection system for aerospace vehicle 306 or spacecraft 308.Aerospace vehicle 306 may be a conventional aircraft.

In this illustrative example, aerodynamic analysis environment 300comprises computer system 310. Computer system 310 includes number ofcomputers 312 in this example. When more than one computer is present innumber of computers 312, number of computers 312 may be in communicationwith each other using wired and wireless communication links. Theselinks may be in a network or other communications system.

In accordance with an advantageous embodiment, aerodynamic analysisenvironment 300 may be implemented as a ground based system, as avehicle based system, or as a system with the various functions thereofdistributed between ground and vehicle subsystems. For example, withoutlimitation, one or more functions of aerodynamic analysis environment300 may be implemented on-board an aerospace vehicle or spacecraft. Anon-board aerodynamic analysis environment of this type may be used foraerodynamic analysis of a vehicle structure while the vehicle is inoperation.

Aerodynamic analysis 302 runs in number of computers 312. Alternatively,aerodynamic analysis 302 may be performed by an aerodynamic analyzer.Aerodynamic analysis 302 generates results 314. Results 314 may be usedto determine whether changes are needed to structure 304. For example,results 314 may be used to determine whether maintenance or redesign ofstructure 304 is needed.

Aerodynamics analysis 302 includes fluid dynamics simulation 316 andaerodynamic heating analysis model 318. Fluid dynamics simulation 316 isa computer simulation of fluid flow over surface 320 of structure 304.Fluid dynamics simulation 316 generates data 322. Thus, data 322 may becomputational fluid dynamics data 324. For example, data 322 may includevalues for various computational fluid dynamics properties such astemperature, pressure, heat flux, velocity, and others. Data 322 isgenerated for number of points 324 in area 326. For example, area 326may be a two-dimensional planar area on surface 320 of structure 304.Data 322 may be stored in database 330. Database 330 may be implementedusing any form of database, data structure, or file format for storingdata 322 in computer system 310. Alternatively, database 330 may beimplemented separate from, but accessible by, computer system 310.

Aerodynamic heating analysis model 318 is used to provide a computersimulation of the heating of structure 304 by fluid flow over surface320 of structure 304. A simulation using aerodynamic heating analysismodel 318 generates second data 332. Second data 332 is generated fornumber of sub-areas 334 of area 328. Sub-areas 334 correspond toportions of area 328. As will be discussed in more detail below, each ofsub-areas 334 includes a number of points 326. Second data 332 also maybe stored in database 330. Results 314 may include data 322, second data332, or both data 322 and second data 332.

A simulation using aerodynamic heating analysis model 318 requires theuse of values 336. Values 336 are fluid flow parameter values forsub-areas 334. In accordance with advantageous embodiment, values 336are generated from data 322 by value calculation unit 338.

Value calculation unit 338 is configured to receive input 340 from user342. User 342 may be a human user. Alternatively, user 342 may be amachine user or a human user acting in combination with a machine user.

User 342 may provide input 340 via input system 344. Input system 344may be implemented in a known manner for providing input 340 from user342 into computer system 310. For example, input system 344 may includeknown input devices such as a keyboard or mouse in combination with adisplay device.

Input system 344 provides user interface 346 for user 342. Userinterface 346 facilitates the entry of input 340 by user 342. Forexample, user interface 346 may prompt user 342 to enter the requiredinput 340. User interface 346 may include a graphical user interface.

Input 340 includes data identification 348 and sub-area identification350. Data identification 348 identifies data 322 to be used by valuecalculation unit 338. For example, data identification may be fileidentification 352. File identification 352 identifies a data filecontaining data 322 to be used by value calculation unit 338.

Sub-area identification 350 identifies a number of sub-areas 334 withinarea 328. For example, sub-area identification 350 may identify a numberof sub-areas for which a simulation using aerodynamic heating analysismodel 318 is to be performed. In accordance with an advantageousembodiment, user 342 may provide sub-area identification 350 in severalways. For example, sub-area identification 350 may be provided asquantity of divisions 354, size of sub-areas 356, or node points 358.

Quantity of divisions 354 identifies sub-areas 354 by identifying aquantity of divisions in which area 328 is to be divided to formsub-areas 334. Size of sub-areas 356 identifies sub-areas by defining asize of the sub-areas in which area 328 is to be divided to formsub-areas 334. Node points 358 identifies sub-areas 334 by identifyingthe location of note points 358 in area 328 corresponding to thelocations of sub-areas 354. For example, node points 358 may be enteredusing two dimensional coordinates to identify the location of nodepoints 358 in area 328.

Value calculation unit 338 is configured to implement determinesub-areas function 360. Determine sub-areas function 360 determines theextent of sub-areas 334 within area 328. Determine sub-areas function360 is responsive to sub-area identification 350 provided by user 342.Operation of determine sub-areas function 360 depends on how sub-areaidentification 350 is provided. If sub-area identification 350 isprovided as quantity of divisions 354, determine sub-areas function 360determines sub-areas 334 by dividing area 328 into the specifiedquantity of divisions. If sub-area identification 350 is provided assize of sub-areas 356, determine sub-areas function 360 determinessub-areas 334 by dividing area 328 into sub-areas 334 having thespecified size. If sub-area identification 350 is provided as nodepoints 358, determine sub-areas function 360 determines sub-areas 334 bydividing area 328 into sub-areas 334 centered on the identified nodepoints 358. In any case, determine sub-areas function 360 may use knowngeometric calculations to determine sub-areas 334 from sub-areaidentification 350.

Value calculation unit 338 also is configured to implement determinepoints in sub-area function 362. Determine points in sub-area function362 determines points 326 in each sub-area 334 of area 328 as determinedby determine sub-areas function 360. Thus, determine points in sub-areafunction 362 is responsive to the determination of the extent ofsub-areas 334 in area 328 by determine sub-areas function 360.

Value calculation unit 338 further is configured to implement determinevalues function 364. Determine values function 364 calculates values 336for sub-areas 334. Determine values function 364 is responsive to points326 determined to be in sub-areas 334 by determine points in sub-areafunction 362. As discussed above, data 322 includes parameter values foreach of points 326. Determine values function calculates values 336 asthe average values of data 322 for the points determined to be insub-areas 334. For example, determine values function 364 may addtogether the parameter values for a given parameter for each of points326 in each of sub-areas 334. The resulting sum is then divided by thequantity of points 326 in each of sub-areas 334. The result is values336 for sub-areas 334. Values 336 calculated by determine valuesfunction 364 may be saved in database 330.

Values 336 determined by determine values function 364 may be providedas output in a variety of forms. For example, output format function 366may format values 336 in Tecplot data format 368, space separated 370,or comma separated 372. Values 336 may be saved in database 330 in thedesired format. Values 336 also or alternatively may be displayed in thedesired format via output system 374. Output system 374 may beimplemented in a known manner for displaying output from computer system310 to user 342. For example, output system 374 may include display 378on which values 336 are displayed to user 342.

Values 336 also may be used in an aerodynamic heating simulation usingaerodynamic heating analysis model 318 to generate second data 332.Second data 332 also may be presented to user 342 on display 378. Sincethe fluid flow parameter values 336 used in such a simulation wereaccurately generated from data 322 in accordance with an advantageousembodiment, the resulting aerodynamic heating data is also accurate andreliable. Furthermore, value calculation unit 338 also operatesautomatically to calculate the accurate values 336 quickly.

Aerodynamic analysis environment 300 may be an aerodynamic conditionanalyzer. In this case, aerodynamic analysis environment 300 may analyzea condition of surface 320 for use by action system 380. Action system380 may implement or initiate surface change 382 responsive to results314 generated by aerodynamic analysis environment 300. Surface change382 may include any change to surface 320 as a response to results 314.For example, results 314 may indicate that surface 320 should berepaired. In this case, surface change 382 may include repair 384.Alternatively, results 314 may indicate that surface 320 should beredesigned. In this case, surface change 382 may include design change386.

For operation as an aerodynamic condition analyzer, aerodynamic analysisenvironment 300 may receive surface condition information 388. Surfacecondition information 388 may include any information describing thephysical characteristics of surface 320. Surface condition informationmay be provided by surface condition detector 390. Surface conditiondetector 390 may be any device or system for generating or otherwiseproviding surface condition information 388.

For example, in an operational environment, surface condition detector390 may include camera 392. Camera 392 provides surface conditioninformation 388 in the form of surface image 394. Surface image 394 isan image of surface 320. For example, surface image 394 may reveal afeature or anomaly in the surface of the thermal protection system ofaerospace vehicle 306 or spacecraft 308.

In another example, surface condition information 388 may include designinformation. For example, surface condition information 388 may includeinformation describing physical characteristics of the current design ofthe thermal protection system for aerospace vehicle 306 or spacecraft308.

In accordance with an advantageous embodiment, aerodynamic heatingcharacteristics of surface 320 may be determined by a computersimulation of surface 320 as defined by surface condition information388. In this case, a computer simulation using aerodynamic heatinganalysis model 318 may employ both surface condition information 388 andvalues 336 to generate second data 332 for current surface conditions asindicated by surface condition information 388.

This second data 332 may be provided as results 314 to action system380. For example, results 314 may include an assessment of whethersurface 320 is flight worthy based on expected environmental conditions,such as environmental conditions associated with spacecraft reentry. Inturn, action system 380 may implement or initiate surface change 382 inresponse to such results 314. For example, second data 332 may indicatethat aerodynamic heating characteristics resulting from a feature oranomaly in the thermal protection system of aerospace vehicle 306 orspacecraft 308 require a repair or redesign of the thermal protectionsystem. In this example, surface change 382 may include repair 384 ofthe thermal protection system or design change 386 to the thermalprotection system, as the case may be.

The illustration of aerodynamic analysis environment 300 in FIG. 3 isnot meant to imply physical or architectural limitations to the mannerin which different advantageous embodiments may be implemented. Othercomponents in addition to and/or in place of the ones illustrated may beused. Some components may be unnecessary in some advantageousembodiments. Also, the blocks are presented to illustrate somefunctional components. One or more of these blocks may be combinedand/or divided into different blocks when implemented in differentadvantageous embodiments.

For example, in some advantageous embodiments, structure 304 may takeforms other than aerospace vehicle 306 or spacecraft 308. For example,structure 304 may be a surface of an aircraft, a ground vehicle, a car,a train, or some other suitable structure or component thereof.Structure 304 may be any structure, made of any material, for which anaerodynamic heating analysis is to be conducted.

In some advantageous embodiments, data 322, second data 332, and values336 may be stored in the same or in different databases or datastructures. For example, data 322, second data 332, and values 336 maybe stored in separate data files in memory or other storage devices. Insome advantageous embodiments, data 322, second data 332, and values 336may be stored in the same or in separate memory or other storagedevices. Such memory or other storage devices may be part of computersystem 310. Alternatively, such memory or other storage devices may beremote from, but accessible by, computer system 310.

In some advantageous embodiments data 322 may be generated in advancefor later use in a simulation using aerodynamics heating analysis model318. For example, data 322 may be generated by running fluid dynamicssimulation 316 in advance of an operational mission of aerospace vehicle306 or spacecraft 308. Data 322 then may be used to generate values 336for use in a simulation using aerodynamic heating analysis model 318during the operational mission.

Furthermore, in some advantageous embodiments, fluid dynamics simulation316 may be implemented in a separate computer system from valuecalculation unit 338 and from aerodynamic heating analysis model 318. Inother advantageous embodiments, value calculation unit 338 may beimplemented in a separate computer system from aerodynamic heatinganalysis model 318.

In some advantageous embodiments, values 336 may be used as input foraerodynamic analysis other than aerodynamic heating analysis usingaerodynamic heating analysis model 318. For example, values 336 may beused as input for any type of aerodynamic analysis where average fluidflow parameter values for areas containing fluid flow parameter valuesfor multiple points are used.

Turning now to FIG. 4, an illustration of a data processing system isdepicted in accordance with an advantageous embodiment. In thisadvantageous example, data processing system 400 is an example of oneimplementation of computer system 310 of FIG. 3. In this advantageousexample, data processing system 400 includes communications fabric 402.Communications fabric 402 provides communications between processor unit404, memory 406, persistent storage 408, communications unit 410,input/output (I/O) unit 412, and display 414.

Processor unit 404 serves to execute instructions for software that maybe loaded into memory 406. Processor unit 404 may be a set of one ormore processors or may be a multi-processor core, depending on theparticular implementation. Further, processor unit 404 may beimplemented using one or more heterogeneous processor systems, in whicha main processor is present with secondary processors on a single chip.As another advantageous example, processor unit 404 may be a symmetricmulti-processor system containing multiple processors of the same type.

Memory 406 and persistent storage 408 are examples of storage devices416. A storage device is any piece of hardware that is capable ofstoring information, such as, for example, without limitation, data,program code in functional form, and/or other suitable informationeither on a temporary basis and/or a permanent basis. Storage devices416 may also be referred to as computer readable storage devices inthese examples. Memory 406, in these examples, may be, for example, arandom access memory, or any other suitable volatile or non-volatilestorage device. Persistent storage 408 may take various forms, dependingon the particular implementation. For example, persistent storage 408may contain one or more components or devices. For example, persistentstorage 408 may be a hard drive, a flash memory, a rewritable opticaldisk, a rewritable magnetic tape, or some combination of the above. Themedia used by persistent storage 408 may be removable. For example, aremovable hard drive may be used for persistent storage 408.

Communications unit 410, in these examples, provides for communicationwith other data processing systems or devices. In these examples,communications unit 410 is a network interface card. Communications unit410 may provide communications through the use of either or bothphysical and wireless communications links.

Input/output unit 412 allows for the input and output of data with otherdevices that may be connected to data processing system 400. Forexample, input/output unit 412 may provide a connection for user inputthrough a keyboard, a mouse, and/or some other suitable input device.Further, input/output unit 412 may send output to a printer. Display 414provides a mechanism to display information to a user.

Instructions for the operating system, applications, and/or programs maybe located in storage devices 416, which are in communication withprocessor unit 404 through communications fabric 402. In theseillustrative examples, the instructions are in a functional form onpersistent storage 408. These instructions may be loaded into memory 406for execution by processor unit 404. The processes of the differentembodiments may be performed by processor unit 404 using computerimplemented instructions, which may be located in a memory, such asmemory 406.

These instructions are referred to as program code, computer usableprogram code, or computer readable program code that may be read andexecuted by a processor in processor unit 404. The program code, in thedifferent embodiments, may be embodied on different physical or computerreadable storage media, such as memory 406 or persistent storage 408.

Program code 418 is located in a functional form on computer readablemedia 420 that is selectively removable and may be loaded onto ortransferred to data processing system 400 for execution by processorunit 404. Program code 418 and computer readable media 420 form computerprogram product 422. In one example, computer readable media 420 may becomputer readable storage media 424 or computer readable signal media426. Computer readable storage media 424 may include, for example, anoptical or magnetic disc that is inserted or placed into a drive orother device that is part of persistent storage 408 for transfer onto astorage device, such as a hard drive, that is part of persistent storage408. Computer readable storage media 424 also may take the form of apersistent storage, such as a hard drive, a thumb drive, or a flashmemory that is connected to data processing system 400. In someinstances, computer readable storage media 424 may not be removable fromdata processing system 400. Computer readable storage media 424specifically excludes pure signals.

Alternatively, program code 418 may be transferred to data processingsystem 400 using computer readable signal media 426. Computer readablesignal media 426 may be, for example, a propagated data signalcontaining program code 418. For example, computer readable signal media426 may be an electro-magnetic signal, an optical signal, and/or anyother suitable type of signal. These signals may be transmitted overcommunication links, such as wireless communication links, an opticalfiber cable, a coaxial cable, a wire, and/or any other suitable type ofcommunication link. In other words, the communication link and/or theconnection may be physical or wireless in the illustrative examples.

In some illustrative embodiments, program code 418 may be downloadedover a network to persistent storage 408 from another device or dataprocessing system through computer readable signal media 426 for usewithin data processing system 400. For instance, program code stored ina computer readable storage media in a server data processing system maybe downloaded over a network from the server to data processing system400. The data processing system providing program code 418 may be aserver computer, a client computer, or some other device capable ofstoring and transmitting program code 418.

The different components illustrated for data processing system 400 arenot meant to provide architectural limitations to the manner in whichdifferent embodiments may be implemented. The different advantageousembodiments may be implemented in a data processing system includingcomponents in addition to, or in place of, those illustrated for dataprocessing system 400. Other components shown in FIG. 4 can be variedfrom the illustrative examples shown. The different embodiments may beimplemented using any hardware device or system capable of executingprogram code. As one example, data processing system 400 may includeorganic components integrated with inorganic components and/or may becomprised entirely of organic components excluding a human being. Forexample, a storage device may be comprised of an organic semiconductor.

In another illustrative example, processor unit 404 may take the form ofa hardware unit that has circuits that are manufactured or configuredfor a particular use. This type of hardware may perform operationswithout needing program code to be loaded into a memory from a storagedevice to be configured to perform the operations.

For example, when processor unit 404 takes the form of a hardware unit,processor unit 404 may be a circuit system, an application specificintegrated circuit (ASIC), a programmable logic device, or some othersuitable type of hardware configured to perform a number of operations.With a programmable logic device, the device is configured to performthe number of operations. The device may be reconfigured at a later timeor may be permanently configured to perform the number of operations.Examples of programmable logic devices include, for example, aprogrammable logic array, programmable array logic, a field programmablelogic array, a field programmable gate array, and other suitablehardware devices. With this type of implementation, program code 418 maybe omitted because the processes for the different embodiments areimplemented in a hardware unit.

In still another illustrative example, processor unit 404 may beimplemented using a combination of processors found in computers andhardware units. Processor unit 404 may have a number of hardware unitsand a number of processors that are configured to run program code 418.With this depicted example, some of the processes may be implemented inthe number of hardware units, while other processes may be implementedin the number of processors.

As another example, a storage device in data processing system 400 isany hardware apparatus that may store data. Memory 406, persistentstorage 408, and computer readable media 420 are examples of storagedevices in a tangible form.

In another example, a bus system may be used to implement communicationsfabric 402 and may be comprised of one or more buses, such as a systembus or an input/output bus. Of course, the bus system may be implementedusing any suitable type of architecture that provides for a transfer ofdata between different components or devices attached to the bus system.Additionally, a communications unit may include one or more devices usedto transmit and receive data, such as a modem or a network adapter.Further, a memory may be, for example, memory 406 or a cache such asfound in an interface and memory controller hub that may be present incommunications fabric 402.

With reference now to FIG. 5, an illustration of a space shuttle isdepicted in which an advantageous embodiment may be implemented. In thisexample, space shuttle 500 is one example of vehicle 200 in FIG. 2. FIG.5 illustrates lower surface 502 of space shuttle 500.

With reference now to FIG. 6, a more detailed illustration of a portionof area 600 of lower surface 502 of space shuttle 500 in FIG. 5 isdepicted. In accordance with an advantageous embodiment, computationalfluid dynamics data may be calculated for area 600. Such a calculationresults in fluid flow parameter values for each of many points 602across area 600.

With reference now to FIG. 7, an illustration of sub-areas and datapoints in the sub-areas in accordance with an advantageous embodiment isdepicted. In FIG. 7, area 600 of FIG. 6 is divided into a number ofsub-areas 704. Each sub-area includes a number of points 602. In thisexample, each sub-area 704 includes the same quantity of points 602. Inother embodiments, each sub-area may include more or fewer points 602.Furthermore, in other embodiments, sub-areas may not all include thesame number of points 602.

With reference now to FIG. 8, an illustration of sub-areas and datapoints in the sub-areas in accordance with another advantageousembodiment is depicted. In FIG. 8, area 600 of FIG. 6 is divided into anumber of sub-areas 806. In this example, each sub-area 806 is definedby a node point 808. Each node point 808 is at the center of a sub-area806. In this example, the various sub-areas do not all include the samenumber of points 602.

As discussed above, the location of each node point 808 in area 600 maybe defined by a two-dimensional coordinate. Sub-areas may be definedaround each node point by locating the next adjacent node point or theedge of area 600 in each X-direction and each Y-direction for each nodepoint. The boundary for each sub-area then is defined by the halfwaydistance to the next adjacent node point in each X-direction and eachY-direction, or by the edge of area 600 if there is no other node pointbetween the node point and the edge in a particular direction.

A process for calculating average computational fluid dynamics valuesfor sub-areas in accordance with an advantageous embodiment is describednow with reference to the flowchart diagram of FIG. 9. The processdescribed may be implemented in aerodynamic analysis environment 300 ofFIG. 3.

The process begins with identifying data to be used (operation 900). Forexample, operation 900 may include identifying a data file containingdata generated by a computer simulation of a fluid flow over a surfacefor expected environmental conditions. The identified data includes datafor a number of points in an area.

Sub-areas of the area then are identified (operation 902). Operation 902may include identifying sub-areas by identifying a quantity of divisionsof the area, by identifying a size of the sub-areas, or by identifyingthe location of node points in the area. Operation 902 includesdetermining the extent of sub-areas within the area. If sub-areas areidentified as a quantity of divisions, the extent of sub-areas isdetermined by dividing the area into the specified quantity ofdivisions. If sub-areas are identified by a size of sub-areas, theextent of sub-areas is determined by dividing the area into sub-areashaving the specified size. If the sub-areas are identified by nodepoints, the extent of the sub-areas is determined by dividing the areainto sub-areas centered on the identified node points. Once thesub-areas are identified, the sub-set of points contained in eachsub-area are determined (operation 904).

From the sub-sets of points determined in operation 904 values for eachsub-area are calculated using the data for the sub-set of points in eachsub-area (operation 906). In accordance with an advantageous embodiment,operation 906 includes calculating each value as an average of the datavalues for the sub-set of points in each sub-area.

The calculated values then may be saved (operation 908). For example,operation 908 may include saving the values in a desired format in adatabase.

The calculated values may be used for an aerodynamic heating analysis(operation 910). For example, operation 910 may include providing thecalculated values as input for a computer simulation using anaerodynamic heating model.

A process for analyzing and changing a surface in accordance with anadvantageous embodiment is described now with reference to FIG. 10. Theprocess described may be implemented in aerodynamic analysis environment300 in FIG. 3.

The process begins with obtaining surface condition information(operation 1000). Operation 1000 may include obtaining informationdescribing the current physical condition of a surface. The surfacecondition information may be obtained using a surface conditiondetector. For example, operation 1000 may include obtaining surfacecondition information in the form of an image of the surface using asurface condition detector in the form of a camera.

Average computational fluid dynamics values for the surface arecalculated (operation 1002). For example, operation 1002 may includesteps 900-908 of the process described above with reference to FIG. 9.

Aerodynamic heating analysis data for the surface then is generated(operation 1004). Operation 1004 may include generating data by acomputer simulation of the current condition of the surface as definedby the surface condition information obtained in operation 1000 using anaerodynamic heating analysis model and the average computational fluiddynamics values provided in operation 1002. Operation 1004 may includeassessing whether the surface is flight worthy based on expectedenvironmental conditions.

The surface then is changed responsive to the results of the aerodynamicheating analysis (operation 1006). For example, operation 1006 mayinclude implementing or initiating a repair or design change to thesurface using the aerodynamic heating analysis data provided inoperation 1004.

One or more of the advantageous embodiments provides a capability togenerate fluid flow parameter data for use in aerodynamic heatinganalysis. For example, in accordance with an advantageous embodiment,computational fluid dynamics data is generated for a number of points inan area on a surface to be analyzed. Sub-areas corresponding to areas ofthe surface for which an aerodynamic heating analysis is to be performedare identified. A computer system automatically determines a sub-set ofthe number of points corresponding to each of the number of sub-areas.The computer system then determines a value for each of the number ofsub-areas using the data for the sub-set of points corresponding to eachof the number of sub-areas. The value is determined by the computersystem automatically as an average of the data for the sub-set of pointscorresponding to each of the number of sub-areas. The resultingaccurately determined parameter values then may be used to perform amore accurate aerodynamic heating analysis.

As will be appreciated by one skilled in the art, advantageousembodiments may be embodied as a system, method or computer programproduct. Accordingly, advantageous embodiments may take the form of anentirely hardware embodiment, an entirely software embodiment (includingfirmware, resident software, micro-code, etc.) or an embodimentcombining software and hardware aspects that may all generally bereferred to herein as a “circuit,” “module” or “system.” Furthermore,aspects of the advantageous embodiments may take the form of a computerprogram product embodied in one or more computer readable medium(s)having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain or store a programfor use by or in connection with any system, apparatus, or device forrunning a program. A computer readable storage medium specificallyexcludes mere propagating signals.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with anysystem, apparatus, or device for running a program.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including but not limited to wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of theillustrative embodiments may be written in any combination of one ormore programming languages, including an object oriented programminglanguage such as Java, Smalltalk, C++ or the like and conventionalprocedural programming languages, such as the “C” programming languageor similar programming languages. The program code may execute entirelyon the user's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the illustrative embodiments are described with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to variousillustrative embodiments. It will be understood that each block of theflowchart illustrations and/or block diagrams, and combinations ofblocks in the flowchart illustrations and/or block diagrams, can beimplemented by computer program instructions. These computer programinstructions may be provided to a processor of a general purposecomputer, special purpose computer, or other programmable dataprocessing apparatus to produce a machine, such that the instructions,which execute via the processor of the computer or other programmabledata processing apparatus, create means for implementing thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

These computer program instructions also may be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions also may be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

The flowcharts and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousillustrative embodiments. In this regard, each block in the flowchart orblock diagrams may represent a module, segment, or portion of code,which comprises one or more executable instructions for implementing thespecified logical function(s). It should also be noted that, in somealternative implementations, the functions noted in the block may occurout of the order noted in the figures. For example, two blocks shown insuccession may, in fact, occur substantially concurrently, or the blocksmay sometimes occur in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustrations, and combinations ofblocks in the block diagrams and/or flowchart illustrations, can beimplemented by special purpose hardware-based systems that perform thespecified functions or acts, or combinations of special purpose hardwareand computer instructions.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof. A number, as used herein withreference to items, means one or more items. For example, a number ofintegrated circuits means one or more integrated circuits.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed.

The description of the different advantageous embodiments has beenpresented for purposes of illustration and description, and is notintended to be exhaustive or limited to the embodiments in the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art. Further, different advantageousembodiments may provide different advantages as compared to otheradvantageous embodiments. The embodiment or embodiments selected arechosen and described in order to best explain the principles of theembodiments, the practical application, and to enable others of ordinaryskill in the art to understand the disclosure for various embodimentswith various modifications as are suited to the particular usecontemplated.

What is claimed is:
 1. A method of aerodynamic analysis of a surface ofan aircraft, comprising: receiving into a computer system surfacecondition information of the surface, the surface condition informationbeing from a surface condition detector and comprising a surface imageof the surface obtained from a camera; identifying data by the computersystem, the data including data for a number of points in an area of thesurface, wherein the data is computational fluid dynamics data generatedby a computer simulation of a flow of fluid over the surfacecorresponding to the area for expected environmental conditions;determining by the computer system an average of the data for the numberof points; and assessing whether the surface is flight worthy using thesurface condition information and the average of the data.
 2. The methodof claim 1, wherein the area corresponds to a portion of the surfacecomprising an anomaly in the surface.
 3. The method of claim 1 furthercomprising changing the surface responsive to assessing whether thesurface is flight worthy.
 4. The method of claim 3, wherein changing thesurface comprises one of changing a design of the surface or repairingthe surface.
 5. The method of claim 1, wherein assessing whether thesurface is flight worthy comprises generating second data using acomputer model of thermal conditions at the surface corresponding to thearea.